Situation Warning And Situation Guidance Of Active Distribution Network

The intermittent distributed generations are included in the active distribution network,which increase the power-supply ability,initiative and flexibility of the distribution network.Owing to the random volatility of distributed generations’output,local voltage levels may be too high on the feeder of the distribution network.The problems have brought many tests on the operating situation of the active distribution network.Simultaneously,with the continuous development of world economy,consumers have high standard of power quality,so we study the security situation warning of the active distribution network,and research the situation guidance on the basis of situation warning of active distribution network in this paper.The main research contents are as follows:Firstly,a model of the total supply capability(TSC)for the active distribution network which considers the main transformer-feeder N-1 safety criterion is proposed.On the basis of the total supply capability model for the distribution network which takes into the main transformer-feeder N-1 safety criterion,we consider the distributed generation and improve the load transfer constraints and N-1 safety constraints in the power-supply ability model of the distribution network.The improved model fully reflects all the information of the distribution network,which can accurately obtain the total supply capability of the network,and provides an accurate database for situation warning of the active distribution network.Secondly,comprehensively considering factors such as system power-supply reliability,system security,economy,and distributed generation fluctuations,an assessment system suitable for the security situation of the active distribution network based on the utility theory is constructed.In the meantime,the operating situation of the active distribution network is accessed and the warning level is divided.At the same time,the principle of improving the fuzzy analytic hierarchy process(FAHP)is analyzed,and the improved fuzzy analytic hierarchy process is utilized to determine the weight of each index.Then the security situation warning value of the active distribution network can be obtained according to the situation warning calculation method.And the influence of factors which access to the distribution network such as weights and distributed generation on the security situation warning of the active distribution network is analyzed.The simulation calculation is carried out in the extended IEEE RBTS-Bus4 system.The results of the calculation example verify the reasonability and accuracy of the security situation early warning method for the active distribution network based on the improved fuzzy analytic hierarchy process.Finally,from the perspective of load,a situation guidance method of active distribution network based on demand response is proposed.The model of total supply capability for the active distribution network considering demand response is constructed,and then a comprehensive optimization model of active distribution network with all situation assessment indicators as the main control objective is established by optimizing the controllable load(demand response).The particle swarm optimization(PSO)is adopted to resolve this optimization model.And the simulation analysis of the extended IEEE RBTS-Bus4 system shows that the proposed method can effectively reduce the network’s power-supply reliability,safety,economy and distributed generation fluctuations,make the network’s operating status better and enhance the security and defense capabilities of the system.